Question

嗨我已经为我的Java Stand alone程序创建了连接池。

好的更清楚..

  private static ComboPooledDataSource = pooledDataSource;

public static void createDataSource(String dbName)
 {

          if(dbName.equals("DB_ONE"))
         {
              pooledDataSource =  new ComboPooledDataSource();

               // Here passing parameters will be different for DB_ONE              
            pooledDataSource.setDriverClass(dbDriver);
            pooledDataSource.setJdbcUrl(dbUrl);
            pooledDataSource.setUser(userID);
            pooledDataSource.setPassword(password);
            pooledDataSource.setMinPoolSize(Integer.parseInt(minCon));
            pooledDataSource.setMaxPoolSize(Integer.parseInt(maxCon));
            pooledDataSource.setMaxIdleTime(Integer.parseInt(maxIdleTime));
            pooledDataSource.setInitialPoolSize(Integer.parseInt(intialPoolSize));
            pooledDataSource.setPreferredTestQuery(testQuery);
        }
        if(dbName.equals("DB_TWO"))
       {
              pooledDataSource =  new ComboPooledDataSource();

               // Here passing parameters will be different for DB_TWO              
            pooledDataSource.setDriverClass(dbDriver);
            pooledDataSource.setJdbcUrl(dbUrl);
            pooledDataSource.setUser(userID);
            pooledDataSource.setPassword(password);
            pooledDataSource.setMinPoolSize(Integer.parseInt(minCon));
            pooledDataSource.setMaxPoolSize(Integer.parseInt(maxCon));
            pooledDataSource.setMaxIdleTime(Integer.parseInt(maxIdleTime));
            pooledDataSource.setInitialPoolSize(Integer.parseInt(intialPoolSize));
            pooledDataSource.setPreferredTestQuery(testQuery);

         }

    }

    public Connection getConnection(String dbName)
     {
          createDataSource(dbName);
       return  pooledDataSource.getConnection();

        }

每当我调用此方法getConnection(dbName)

时，在我的DAO课程中

在两个不同的数据库之间频繁地进行切换..对于每个连接调用，再次创建特定数据库池。

我不想创建重复的池......

如何避免创建新的connection pool？

任何帮助谢谢你。

Answer 1

查看内部方法：

return  pooledDataSource.getConnection();

无论何时调用方法，您都要创建新连接。只需输入pooledDataSource.getConnection（）;内部静态内容：

//change private variable to Connection
private Connection connection
static{

         pooledDataSource =  new ComboPooledDataSource();

        pooledDataSource.setDriverClass(dbDriver);
        pooledDataSource.setJdbcUrl(dbUrl);
        pooledDataSource.setUser(userID);
        pooledDataSource.setPassword(password);
        pooledDataSource.setMinPoolSize(Integer.parseInt(minCon));
        pooledDataSource.setMaxPoolSize(Integer.parseInt(maxCon));
        pooledDataSource.setMaxIdleTime(Integer.parseInt(maxIdleTime));
        pooledDataSource.setInitialPoolSize(Integer.parseInt(intialPoolSize));
        pooledDataSource.setPreferredTestQuery(testQuery);
        //here is new line
        connection = pooledDataSource.getConnection();
}

并在方法中执行：

public Connection getConnection()
     {
       return  connection;

        }

Answer 2

也许你可以考虑这样的事情：

private static Map<String, ComboPooledDataSource> dataSources;

static {
    dataSources = new Map<String, ComboPooledDataSource>();
}

public static void createDataSource(String dbName) {
    ComboPooledDataSource pooledDataSource =  new ComboPooledDataSource();
    if(dbName.equals("DB_ONE")) {
        // Here passing parameters will be different for DB_ONE              
        pooledDataSource.setDriverClass(dbDriver);
        pooledDataSource.setJdbcUrl(dbUrl);
        pooledDataSource.setUser(userID);
        pooledDataSource.setPassword(password);
        pooledDataSource.setMinPoolSize(Integer.parseInt(minCon));
        pooledDataSource.setMaxPoolSize(Integer.parseInt(maxCon));
        pooledDataSource.setMaxIdleTime(Integer.parseInt(maxIdleTime));
        pooledDataSource.setInitialPoolSize(Integer.parseInt(intialPoolSize));
        pooledDataSource.setPreferredTestQuery(testQuery);
        dataSources.put(dbName, pooledDataSource);
    } else if(dbName.equals("DB_TWO")) {
        // Here passing parameters will be different for DB_TWO              
        pooledDataSource.setDriverClass(dbDriver);
        pooledDataSource.setJdbcUrl(dbUrl);
        pooledDataSource.setUser(userID);
        pooledDataSource.setPassword(password);
        pooledDataSource.setMinPoolSize(Integer.parseInt(minCon));
        pooledDataSource.setMaxPoolSize(Integer.parseInt(maxCon));
        pooledDataSource.setMaxIdleTime(Integer.parseInt(maxIdleTime));
        pooledDataSource.setInitialPoolSize(Integer.parseInt(intialPoolSize));
        pooledDataSource.setPreferredTestQuery(testQuery);
        dataSources.put(dbName, pooledDataSource);
    }
}

public synchronized Connection getConnection(String dbName) {
    if (!dataSources.containsKey(dbName)) {
        createDataSource(dbName);
    }
    return  dataSources.get(dbName).getConnection();
}

使用此解决方案，您只能在需要时创建数据源（但在创建后保持活动状态），并且可以从所需的数据源访问连接，而无需创建新池。

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